Composite firearm barrel



Aug- 5 1958 H. l. DAY 2,845,741 v COMPOSITE FIREARM BARREL Filed Apriz; 1955 |NvEN-roR Hurry I. Da y ATTORNEYS e shells under normal conditions,

vUnited States Patelmltj()A 2,845,741 Y ooMroslrn. FiREARM BARREL Harry I. Day, Wellesley, Mass., assignor to Olin Mathieson Chemical Corporation, New Haven, Conn., a corporation of Virginia f l yApplicatimi April 27, 195s, SerialrNo. 504,293 6 claims. (ci. 4z7isjl Y This invention relates to a novel structural element which is outstandingly useful for the attainment of in-l creased stiiness of la pliant member, such `as is encountered on extremely light-weight lirearm barrels of com-y posite construction-and |similar tube-like members. A'Ihe invention will -be described with particularreference to firearm barrels of such lightweight construction and which are characterized by the provisionrof a projectile discharge bore throughwhich 'ar suitable charge of propellant, such l, as smokeless powder, dischargesa projectile at high speed. y

y To secure the utmost accuracy of such barrels, it is v2,845,741 Patented Aug. 5,A i958 2 t e will be contained andnot be scattered. The barrel of Ithe present invention4 is of a composite type, the corn` ponents `of which cooperate to lend to the barrel the ness and strength for certain types of barrels, it. has been determinedthat under certain conditions and proportions, this construction can develop an excessive deflection or muzzle drop.

Although my invention is presently described in con-v nection with a rilie or shot-gun barrel, it is within the `scope of myconception that gun barrels of much larger supports, the trunnions of necessity are placed Vrearward bore and greater length may be constructed according to the disclosure of copending application Serial No. 486,322.. It'is wellknown that, in the design of guns of `larger bore, which are mounted on' carriages or other of center and additional weight must be included in the barrel, rearward of the trunnions for balance andl forward of the trunnions to secure thenecessary stiliness for reducing/the `muzzle deflection to a minimum.

necessary that the tubes o r barrels land particularly ltheir bores be maintained in a straight line and the deflection of the muzzle'redu-ced to a minimum. The travel of the projectile tends to correct any deection of the bore and thereby sets yup a vmuzzle vibration which affects accuracy. Alloy and rcarbon* steels have been extensively used 1n gun barrels which are capableof withstandingthe stresses resulting from 'the tiring of cartridges and shot a Aand are also capable of withstanding, toa great extent,abnormal stresses which are encountered, when a shot shell or cartridge .is tired against an obstruction in the. barrel. Properlymade,

suchg'un'ba'rrels exhibit the important and desirable .char-A acteristics of non-fragmentation if the barrelshould ,burst because of excessive loading Opnewof` the' ends' constantly sought in `gunrdesigning and manufacture is lightness. Butunless the barrel isV made ofk a different materialfrom those heretofore used,v

thel'weightof the barrel cannot be reduced'withoutsacrifitting-strength and thusreducing the ability of thenbarrel to withstand abnormal stresses to which it might be subjected if the barrel/is obstructed when the `gun is tired. 'llhe yratio of strengthy to weight is a matter'ofcompr'omise notn permitting muchA variance in what is looked upon as standard practice withy the materials heretofore available for manufacture of gun barrels.

lAluminum. hasv been tried in shot-gun barrels withy apparent initial success.A That is a shot-gun with an aluminum barrel produced excellent enduranceA and wear, ycharacteristics under normal conditions. yButal satisfaetory gun, either sporting or military, must be designedV topmeet yabnormal, conditions, such as firing of a shell when the barrel is clogged.` Becauseof this, gun manufacturers, submit newpgun' barrel designs to certain tests in .which shells arefired through/barrels against certain When aluminum barrels predetermined obstructions. were tested in this (manner, it was found that instead of bulging or burstingas present-day steelbarrels do, the aluminum was shattered and fragments were blown in allldirections," thus j producing a `very dangerous condition.Y

,In 'the` present invention, I provide a light-Weight barrel forfrearms of. alljkinds which will withstand, withoutY significant change, tiring conditions under lWhich present-v da'yfs'tee'll alloy'bar'rels would bulge or burst.- However,

This problem is exaggerated in guns mounted onV vessels -irearm barrel of the composite type, the components of which may be arrangedrto lend to the barrel vastly increased strength under high intensity stresses of very short duration not only radially but longitudinally aswell, thereby not only rendering the barrel burst-and-fragmentation proof as aforementioned, but also producing a .stitened structure which further permits the safe use of higher energy propellants, with the ensuing advantage of permitting the firing vfrom thelbarrel ofprojectiles at greater velocity in a flatter trajectory than was possi-ble heretofore, with a substantial decreased barrel weight.

While the use of materials having widely diiierent resonance characteristics produces 'amore effective and satisfactory damping of the vibrations produced on tiring the projectile, they also havea tendency to produce a barrel more easily deflected. The accuracy of presentday riiies is known to be adverselyl aiected by the vibra-A tions which are induced through the oscillatory nature if'the gun should be liredunder even more extremev cony Vj v *n Y "a jacket bonded to the liner and formed of a multitude ditions causing the liner -fto burst, the-metal particlesA of the propellant burning and also by the `stresses transmitted to thebarrel material through the .movementof f the projectile down theybore. The tendency of the projectile, in ight through the bore, to correct the muzzle deection is a contributing cause to excessive muzzle vibration. vDifferences in vibration load, with respect to the projectile exit produce varying transverseforces which are responsible for a considerable proportion of the shift of the flight path in successiveshots However, where thev barrel is formed of materials having widely different resonance` periods, the early damping of these vibrations tends to significantly minimizey transverse forces on the projectile and thus to decrease variations in the flight path vfromishot to shot.'

To attain these ends I provide a firearm barrel type which has as one of its components 'an inner liner of any suitable material, such as aluminum, steel, stainless steel, or titaniunnfor instance, which is primarily relied on to provide in the barrel a suitable projectile discharge,

bore, that may be rifled,` and which will withstand the erosive action of projectiles andk hot powder gases, and has suicient hardness to withstand engraving pressures of the projectile, and which has for anotherv component.

of light-weight fibers of relatively high individual strength, which is primarily relied on to lend the barrel the overall strength require@ to render the same burstproof as aforementioned and an additional component consisting of a sheet of foil material wrapped around the liber component. The liner distributes the stresses to the jacket fibers most uniformly causing them to act in unison rather than individually while the foil wrapper supports the liner and jacket fibers to impart stiffness to the elongated tube member.

It is a further object of the present invention to provide a rearm barrel of the composite type in which the fibers wound on the liner are supported and stiffened by a sheet of metal foil.

It is a still further object of the present disclosure to provide a composite firearm barrel having a metal tube, superposed layers of fibers, woven tape or cloth and resin and a casing of foil wound on the exterior surface of said fibers to form a rigid construction.

lt is still another object of the present invention to produce a composite firearm barrel in which the tube may be of metal, the fibers of the jacket may be of any suitable light-weight material of high strength properties, with a sleeve of metal foil encasing the composite structure.

Further objects and advantages will appear to those skilled in the art from the following considered in conjunction with the accompanying drawings.

In the accompanying drawings certain modes of ca rrying out the present invention are shown for illustrative purposes:

Fig. l is a side view of a mounted composite rearm as constructed according to the present invention;

Fig. 2 is a longitudinal section through a composite rilie barrel embodying the present invention and showing the inner metal tube, the liber winding and the foil wrapping, the foil wrapping being exaggerated for clarity;

Fig. 3 is an enlarged cross-section of the barrel on line 3-3 of Fig. 4 during assembly and shows the reinforcing foil wrapping partly in place;

Fig. 4 is a top plan view of a barrel partially wrapped;

Fig. 5 is a side view, partly in longitudinal Section, showing the present invention as applied to a shot-gun barrel;

Fig. 6 is a perspective View of another form of applying the invention which may take the form of 'a sleeve of either wound cross-section or extruded form to be slipped over the basic winding.

Referring to the drawings and more particularly to Figs. l and 2 thereof, the reference number 20 designates a portion of a firearm, such as is shown and described in U. S. Patents 2,099,035 and 2,155,512 having a receiver 21 on the forward end of which is mounted a barrel 22. A conventional breech bolt 23 -is movable in the receiver 21 into and from closed position (Fig. 2) in which to lock a cartridge C to be fired in the breech end of the barrel. The breech bolt 23 carries a conventional firing pin and associated mechanism for discharging the cartridge.

The barrel 22 comprises an inner liner 24 and a fibrous jacket 25. The liner 24 is over the greatest part of its length diametrically reduced externally to leave a cylindrical wall 26 of relatively small thickness, a non-reduced end of the liner formingrthe breech end 27 of the barrel which may conveniently be threaded at 28 for its reception in the receiver 2l. As the exemplary barrel 22 is a rilie barrel, the projectile discharge bore 29 of the liner 24 may be rilled as at 30. The liner may be formed of metal, or other suitable materials, as the jacket is also relied upon to provide the required physical properties to withstand the high intensity, short duration stresses which are encountered when the gun is red under abnormal conditions, and to prevent fragmentation if the barrel does burst. As set forthin said copending application, Serial No. 486,322, high intensity, short duration stresses in connection with av firearms barrel means pressures greater than 3500 p. s. i. and periods of l5 milliseconds or less. This` permits lightening of the barrel by use of lighter-weight and less rigid metals than have heretofore been used in the manufacture of gun barrels. While the use of the above mentioned construction produces a sufficiently strong, light-weight construction to withstand the forces of explosion, certain combinations which may be utilized are conductive of exaggerated whip or deflection and it is the purpose of the present invention to supplement the composite structure shown in co-pending application Serial No. 486,322 to produce a stiffened structure which will reduce muzzle deflection to a minimum.

The preferred barrel may be constructed with a jacket 25 of fibrous material as described `in the copending application before mentioned but upon the exterior surface of the jacket 25, I arrange a coating of metal foil 31.

This metal foil coating may be a single sheet bonded to the fibrous jacket or it may be formed of several layers of material, the several layers being suitably bonded one to the other. I have found that one of several resin binders may be used with satisfaction although certain metallic coatings may preferably be brazed or welded. The composite structure forming the body of the barrel as described in the copending application is of such texture and hardness that it may be ground to a smooth surface and to close tolerances. This feature permits the use of a preformed sheath in place of the wrapping, the sheath being shrunk over the prepared exterior of the jacket and fitting thereto in a manner to utilize the maximum compressive characteristics of the foil used.

The foil coating may be of any of the non-corrosive metals such as brass or stainless steel to protect the barrel. The preferred construction as shown further produces a barrel which has a lower heat factor for continuous lire than can be obtained with the standard metal barrel.

In accordance with the preferred method, the surface of the jacket 25 is finished to the desired profile and dimensions to accommodate the particular type and power of the ammunition to be used. Upon the exterior surface of the jacket, I wind a layer of thin metal foil 31, preferably stainless steel, and secure it thereto by a suitable binder. Excellent results have been achieved with a binder known to the trade as Epoxy which are condensation products of epichlorohydrin and a polyhydric phenol, such as diphenylolpropane. It is within the concept of my invention that the metal foil sheathing may be any one of several available metals and may further consist of one -or several layers of foil, suitably bonded together in order to obtain the degree of stiffness necessary for the particular type of ammunition used.

Although the preferred method of applying the stiffen ing coat is by winding the foil on the preformed ber coating, it is within the concept of my invention to prepare the foil wrapper in the form of a seamless, welded, or extruded tube and telescope the prepared tube over the surface of the barrel, employing suitable adhesive to secure the tube in place.

In Figs. 3 and 4 I have illustrated the application of the foil wrapping 31 by winding. As shown, a sheet 32 of foil of the desired thickness may be wrapped around the barrel of the firearm by rotating the barrel until the desired number of layers of foil have been applied. The foil may be coated with a binder of the type heretofore described prior to wrapping.

Fig. 5 shows the invention applied to the barrel of a shot-gun. It is generally similar to the rifle barrel heretofore described except the liner 24 is not rilied. This liner is formed of metal or other suitable material, as heretofore described, and is surrounded by the jacket I 25. The foil coat 31 is then secured over the jacket to complete the barrel construction.

ybefore they are wound on the liner.

In the form of the invention .shown in Fig. 6, liner24 is provided with collar 33 at each end, the collars being either made integral with the liner or secured thereto. Jacket 2S is then placed' on the liner between the collars andfinished ilush vwith the collars. The foil coat 31 is then applied, either by wrappingl or in the form of a preformed tube. It is secured to collars 33 by brazing or welding and to the jacket 25 by a binder, such as the resins herein-disclosed.

The fibrous jacket 25 may be formed by any of a variety of methods. It is essentially composed of a multitude of fibers or laments of relatively high strength properties which are bonded to each other and to the j liner 24 in'mutual stress-transmitting relation. A strand,

or strands, of glass fibers or other high strength laments may be wound on the liner 24 in superposed layers. The binder is preferably applied to the brous strands The binder may be applied by brushing, spraying, immersion, or preimpregnation prior to winding.

Among various fibers which I have tested, glass bers have produced the best results. Good results are also obtained with other mineral bers, also with nylon, Dacron, Teflon, Orlon and other linear polymer bers, for instance. In general I believe any ber of high strength properties will serve the purpose of lending suicient strength to av composite barrel to render it substantially burstproof under obstructed ring conditions.

. As stated, the composite structure of the present vinvention is generally similar to the construction disclosed in copending application Serial No. 846,322, lecl` February 7, 1955, but it is within the concept of the present invention to incorporate the foil wrapping construction in any l composite structure wherein the body may be stiffened by tensile and compressive properties of the foil.

I claim: l 1. A composite firearm barrel, comprising a liner provided with a projectile discharge bore and having inadequate strength to withstand ordinary internal firing pressures, an outer jacket thereon formed of a multitude of glass bers bonded to each other and to said linear in mutual stress-transmitting relation and adding sufficient strength to that of said liner to preserve the conguration of the latter and to .render the composite barrel suiciently strong to withstand the pressure generated during the propellant burning cycle, and a layer of metallic foil covering the jacket to increase the stiffness and rigidity of the barrel. v

2. A composite rearm barrel, comprising a liner provided with a projectile discharge bore and having such small wall thickness as to lack strength to withstand ordinary internal ring pressures, an outer jacket thereon formed of a multitude of glass bers bonded to each other and to said liner in mutual stress-transmitting relation land having suicient strength to reinforce said barrel should burst under obstructed ring conditions,

, liner so that the same will withstand ordinary internal vring pressures and will be fragmentation-proof if the and a layer of'metallic foil covering the jacket to'increase the stiffness and rigidity of the barre1.

3. A composite rearm barrel, comprising a liner having a projectile discharge bore, an outer jacket' thereon formed of a multitude of glass fibers Wound in successive layers and bonded to each other by a binder by which they are secured to each other and to said liner in mutual stress-transmitting relation, said fibers adding suicient strength to that of said liner to render the barrel substantially burstproof under obstructed ring conditions, and a layer of metallic foil covering the jacket to increase the stiffness and rigidity of the barrel. t

4. A composite rearm barrel, comprising a liner provided with a projectile discharge bore and having such vsmall Wall thickness as to lack strength to withstand ordinary internal ring pressures, an outer jacket thereon formed of a multitude of glass bers wound in successive layers and bonded to each other bya binder by which they are secured to each other and to said liner irl-mutual stress-transmitting relation, said bers adding suiicient strength to that of said liner to preserve the configuration of the latter and render the barrel `substantially burstproof under obstructed ring conditions, and a layer of metallic foil covering the jacket to increase the stiness and rigidity of the barrel.

5. A cylindrical vessel comprising a composite structure consisting of a metallic liner, an outer jacket thereon formed of a plurality of bers bondedr to each other and to said liner in mutual stress-transmitting relation, said bers adding suicient strength to said liner thatA said composite structure is capable of withstanding pressures greater than 3500 p. s. i. for periods of 15 millisecondsv or less, a layer of metallic foil coveringthe jacketand closure means independent of said composite structure for closing, atleast, one end of said vessel.

6. A cylindrical vessel comprising a composite structure consisting of a metallic liner, an outer jacket thereon formed of a plurality of glass bers bonded to each other and to said liner in mutual stress-transmitting relation, said fibers adding sufficient strength to said liner that said composite structure is capable of withstanding pressures greater than 3500 p. s. i. for periods of 15 milliseconds or less, a layer of metallic foil covering the jacket and closure means independent of said composite structure for closing, at least, one end ofsaid vessel.

References Cited in the file of this patent f UNITED STATES PATENTS Ramberg May l, 1956 

